Strange messages/codes

So my H3 has been down for a few weeks. We know it's an electrical problem that happened after a mud run. Starter was changed, battery terminals were changed, all new AGM battery put in also.

So even after changing these things the H3 wouldn't start. Talking to a member from my offroad club, he told me to remove and clean each relay and fuse one by one with electrical cleaner which I did. The H3 started. I let it run for 30-40 minutes while I cleaned the interior. I turned it off to see if it would start up again and it did. But not a third time. I then got these generic/aftermarket relays and I swapped them with the starter relay and run/crank relay. It started up multiple times. But it also displayed messages;

parking brake
abs fail
traction control fail
brake fluid


what could it be? Want to get the rig ready for Black Friday so I can join H40 at Last Chance Canyon

Vdawg1115 said:

So my H3 has been down for a few weeks. We know it's an electrical problem that happened after a mud run. Starter was changed, battery terminals were changed, all new AGM battery put in also.

So even after changing these things the H3 wouldn't start. Talking to a member from my offroad club, he told me to remove and clean each relay and fuse one by one with electrical cleaner which I did. The H3 started. I let it run for 30-40 minutes while I cleaned the interior. I turned it off to see if it would start up again and it did. But not a third time. I then got these generic/aftermarket relays and I swapped them with the starter relay and run/crank relay. It started up multiple times. But it also displayed messages;

parking brake possibly the park brake area of the rear rotor is packed with mud possibly holding the park brake shoes (park brake works off of shoes that are inside the rear rotor, rotor is like a hat. It usually does not take much for the park brake to be pushed in for the message to come on, so possibly mud is holding the shoes in just enough to pull the park brake lever down (only a guess) but also could be the park brake switch on the park brake is out of adjustment, broken or connector disconnected.
abs fail check the four wheel speed sensors for mud
traction control fail same as above
brake fluid check the connector on the left side of the brake booster for mud.


what could it be? Want to get the rig ready for Black Friday so I can join H40 at Last Chance Canyon

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Some swags.

Also, you mention codes...what codes? The codes might help to narrow the problems

f5moab said:

Some swags.

Also, you mention codes...what codes? The codes might help to narrow the problems

Click to expand...

Okay, not codes....just them error messages. Should I bust out the power washer for this?

Clearly something is up with the braking system. I suspect a cut (or leaking) brake line. I assume that if enough brake fluid leaks to register a BRAKE FLUID warning message, it might just trigger all of those other systems as well. Parking brake is all cable operated but, I frequently bump my pedal climbing in and out. All it takes is one or two clicks, for it to display the message.

4speedfunk said:

Clearly something is up with the braking system. I suspect a cut (or leaking) brake line. I assume that if enough brake fluid leaks to register a BRAKE FLUID warning message, it might just trigger all of those other systems as well. Parking brake is all cable operated but, I frequently bump my pedal climbing in and out. All it takes is one or two clicks, for it to display the message.

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I refilled my brake fluid recently. I do know that my pads are thin and should be changed soon though, would that trigger it too?

Perhaps its over-filled? Not sure if that would trigger the issues you're having or not. Most cars have a small gauge-strip on the plastic master cylinder reservoir with a fill-line on it.

If your pads are very thin...you'll need to manually push the caliper pistons back to their original starting position, when you install the new pads. (I use a big pair of channel locks for this). Additionally, if you filled-up the master cylinder when the pads were thin...you'll have to use a turkey-baster to suck some fluid out of the master cylinder when you replace the pads. Otherwise when you squeeze the channel locks at the calipers...it will spooge a bunch of brake fluid out the top of the master cylinder and all over the place.

Of course GM located some critical wiring nearby, :roll: so keeping the fluid from overflowing is even more important than it would be on most vehicles.

So I got home and it's already dark but I took the power washer to all four wheels. Wanted to make sure the brakes and the parking brake cable was clean. Since the H3 gave me ABS fault, traction control fail, Service 4wd, and brake fluid issues. Found a little piece of wood on the front drivers side brakes along with a ton of pine needles. Power washed from both sides. The parking brake cable was also clogged up with mud. Power washer that too and so far no more errors. Haven't taken it out for a spin yet.....but would the piece of wood alone cause that much fuss?

Sounds like it.
I recently was up running through the woods up around Onion Mountain Look-out and crossed a new cut sight (fire prevention road) and had a branch hit between the frame and the cable just right. it was about a 2 1/2 inch diameter fir branch the front tire must have kicked up. Took me about 30 minutes to figure it out and was dead in the water until I saw it.

Oh hell yes. That wood (would) do it for sure. The H3's electronic traction aides are crazy sensitive.

Depends on where that piece of wood was actually located. If blocking a sensor, absolutely.
As for the the park brake, as I noted, the pedal is very sensitive, does not need to be pushed down that much for the switch to close stating park brake is applied so mud in the cable could hold it just enough to prevent the pedal from coming back up all the way.
Brake fluid sensor is really a switch and I don't believe it will be affected by overfilling the master cylinder. Can't say for sure, but factory schematics show it as a switch; not an actual sensor.

The H3 wheel sensors are located deep inside the sealed bearing hubs, so it would be very difficult to "block" the sensor itself (like the exposed 1990s sensors). However if that chunk was somehow limiting the travel of the caliper's pistons, it would surely cause an issue. The master cylinder is unlike any other vehicle I've worked on, and I assume the line pressure of each corner is independently monitored (for TCS, ABS, and Stabilitrac). So if there is any pressure related issue at any corner...it will light up the dash like a Bruno Mars concert.

A common problem with H3s is crap like that getting jammed between the rotors and the dust shields. I've never known it to set a code but, it sure can make some horrendous noises.

Lastly...maybe the parking brake cable was behind all the alerts? Like many codes on the H3...sometimes your best course of action is to be glad it's gone, and hope it doesn't come back!


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The piece of wood was lodged towards the front on the inside of the brakes. Couldn't see it until I turned the wheel all the way to the driver's side and crawled under. Had to play around with it to free it

Somewhat related, but I don't think it ties in directly . . . I had ABS fault issues once when my calipers were off and someone pushed the brake pedal to the floor. it extended the pistons and the resulting errors had to be reset by a professional tool. Just throwing that out there in case there are actually two issues at hand here but hopefully you've got it addressed.